package demo13;

import java.text.DecimalFormat;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        DecimalFormat j=new DecimalFormat("0.00");
        Scanner sr=new Scanner(System.in);
        int m=sr.nextInt();
        int s=sr.nextInt();
        int d=sr.nextInt();
        double ym=(d/1.6)/(m*(1.0/60)+s*(1.0/3600));
        System.out.println(j.format(ym));
    }
}
